1. Field of the Invention
This invention is generally directed to portable room air purifiers and more specifically to a compact portable room air purifier wherein air is discharged after passing through a filter element through a scroll outlet where the air is generally directed tangently with respect to the axis of rotation of a fan used for conveying air therethrough. An outer deflector wall is mounted in spaced and converging relationship with respect to the scroll wall so as to define a tapering passageway through which the air is exhausted generally radially of the unit. In the preferred embodiment, the filter element is a HEPA filter of cylindrical configuration which is mounted within a cover. A motor is mounted centrally of the filter element for driving the fan. The deflector wall is designed to provide a substantially annular opening through which air is exhausted as it is channelled generally circumferentially about the base of the unit.
In the preferred embodiment, the cover is interlocked with a base member with an electrical switch being positioned to deactivate power to the motor in the event the cover is removed or unlocked from the base or in the event the cover becomes shattered thereby releasing pressure of the cover relative to the base thus providing safety and eliminating any possibility of injury from accidental contact with the fan.
In some embodiments, two or more scrolls and/or deflectors may be utilized to distribute the air generally evenly with respect to the periphery of the unit.
2. History of the Related Art
There is an ever increasing need to provide clean air environments both at home and in the work place. Especially in urban areas where pollutant levels are in excess of those recommended for good health, it is necessary to upgrade living and work environments by removing harmful contaminants from the air.
Airborne pollutants contribute to respiratory infections and illnesses and can be especially damaging to individuals with respiratory problems including allergies or from Asthma. Symptoms of high pollutant levels are burning eyes, nose and throat irritations, headaches, dizziness, coughing and sneezing. Individuals are constantly inhaling particles of dust, smoke, pollen, mold spores, acids, bacteria, viruses, animal hair, soot, and harmful chemicals.
In an effort to provide some relief from airborne pollutants, many offices and homes utilize central filtering systems to remove particles from the air. Unfortunately, such centralized systems, which are economically available, do not remove more than approximately 80-85% of the particles in the air and are only effective on particles which are approximately one micron or larger.
The need to have substantially purified air has resulted in the creation of special filter elements which are defined as HEPA filters. HEPA stands for High Efficiency Particulate Air filters which by, federal standard, are filters with a minimum efficiency of 99.97%. The industry defines HEPA filters as those filters which are efficient in removing 99.97% of airborne particles of a size of 0.3 micron or larger.
Although such HEPA filter elements where originally designed for use in ultra clean environments including laboratories, electronic and biologically clean rooms, hospitals and the like, such filters have been used in portable structures which may be utilized in individual room environments.
In U.S. Pat. No. 4,629,482 to George B. Davis, one type of portable HEPA room air purifier is disclosed which has specific utility in allowing for a fairly uniformed distribution of filtered air from the unit and wherein the unit is designed to provide an indication of when the filter cartridge is becoming clogged and should be replaced. The unit incorporates a cylindrical HEPA filter so as to increase the overall surface area of the filter material and the filter is mounted within a housing having an annular discharge adjacent its base. A centrifugal fan is utilized to draw air through the filter and discharge the air radially outwardly of the annular discharge. Due to the configuration of the unit, it is necessary to space the base of the apparatus from the main housing in which the cylindrical filter is mounted which requires that the apparatus be designed somewhat larger than some consumers may prefer.
In view of the foregoing, it has become necessary to overcome the physical detriments of prior art portable filter structures by providing compact portable units without however, affecting the capability of the units to uniformly distribute and filter air within a room.